Recording tape, such as magnetic recording tape, provides a dense medium for the storage of large quantities of data. The data is typically written to the tape in a longitudinal, multi-track format. The dense data storage results from a high linear data density in the longitudinal direction and from closely packing the multiple tracks. The longitudinal tracks are closely packed by both reducing the width of each track and by reducing the distance between tracks. High track densities are achieved by recording tape which has track following servo information thereon and by tape drives which employ movable tape heads and track following servos. Thus, as the recording tape is moved longitudinally along a tape path and across the movable tape head, the track following servo is responsive to the track following servo information of the recording tape for moving the tape head laterally with respect to the tape path to follow any lateral movement of the recording tracks of the recording tape and maintain alignment of the tape head with respect to the recording tracks.
Conventional track following tape drives precisely fix the lateral position of one edge of the tape by means of tape guides having at least one fixed flange. The tape guides are positioned closely adjacent to and on either side of the tape head, in the longitudinal direction of the tape. Since the tape typically is not cut with perfectly straight edges, the tape guide at the edge opposite the fixed flange is often compliant, accommodating variations in the tape width.
However, the tape typically winds onto reels in a non-uniform profile which results in lateral tape motion at the head and tape guides when the tape is unwound at typical tape speeds. Thus, an outer set of tape guides, such as illustrated in U.S. Pat. No. 5,447,279, Janssen et al., are positioned further from the tape head, outside of the fixed tape guides, in the longitudinal direction of the tape. The outer set of tape guides is compliant on both sides of the tape and intended to apply gentle tape guidance and cause a "coarse correction" of the tape and reduce the force of the one edge of the tape against the fixed flanges of the inner tape guides. In such an arrangement, the inner tape guides are often called the "fine" tape guides.
This "coarse correction" tends to be insufficient to counter the collision of the tape edge and the fixed flanges of the inner tape guides. The result of this collision can be a damaged tape due to wear, buckling, stretching, and breakage of the tape. The tape drive can also be damaged by wear and by the accumulation of debris resulting from the collisions of many tapes with the fixed flanges.